[1,5]‐Hydride Transfer/Cyclization of ortho‐Amino Alkynyl Fischer Carbene Complexes: A Useful Tool for the Synthesis of Quinoline Derivatives

Abstract An efficient method for the synthesis of compounds containing a quinoline moiety by using o ‐aminophenyl alkynyl Fischer carbene complexes as starting materials is described. The reaction is based on a cascade process involving [1,5]‐hydride transfer/cyclization to afford new alkenylcarbene complexes with quinoline moiety 2 . The reaction of alkenyl complexes 2 with unsaturated substrates such as electron‐poor alkynes afford furo[2′,3′‐3,4]cyclopenta[1,2‐ c ]quinolinone derivatives 6 and (1,2‐dihydroquinolin‐3‐ylvinyl)malonates 12 when propiolic aldehydes and propiolates are used, respectively. The reactivity of the alkenylcarbene complexes was also studied by using 1,3‐dienes to afford cyclohepta[ c ]quinolinones 17 when Danishefsky's diene is used and 3‐pirimidinylquinoline derivatives 21 when 4‐amino‐1‐azadienes are employed.